Search contact by phone number

In my app, user writes a phone number, and I want to find the contact name with that phone number?

I usually search the contacts like this:

Cursor cur = getContentResolver().query(ContactsContract.Contacts.CONTENT_URI,
            null, null, null, null);

But I do this to access all contacts... In this app I only want to get the contact name of the given phone number... How can I restrict the query?

Or do I have to go trough all contacts and see if any has the given phone number? But I believe that this can be very slow this way...